Signal Noise Patents (Class 375/227)
  • Publication number: 20080101449
    Abstract: A signal receiving apparatus includes an indicating unit, a receiving, a system unit which comprises a plurality of electronic components to provide signal processing, a storing unit to store information related to a noise level, and a controlling unit to estimate a signal power level of the data received by the receiving unit, to compare the estimated signal power level of the data with the noise level generated by a power supply to the system unit, and to control the indicating unit to indicate whether the data can be received.
    Type: Application
    Filed: September 6, 2007
    Publication date: May 1, 2008
    Applicant: Samsung Electronics Co., Ltd
    Inventor: Houk Wang
  • Publication number: 20080095222
    Abstract: A method of selecting linked metric measurements from at least one of open loop and closed loop measurements is disclosed. The method includes sending by a first node a first radio communication and receiving by a second node the first radio communication over a communication link. The method also includes estimating by a second node dynamics of the communication channel using at least one of the variance and mean deviation of linked metric measurements. The link metric measurements are at least one of symbol error rate (SER), packet error rate (PER), frame error rate (FER), bit error rate (BER), signal to noise ration (SNR), and received signal strength (RSS). The method also includes the use of the above link metric measurements by the second node as Open Loop metrics and the sending back of these metrics to the first node for use a Closed Loop metrics by the first node. The method also includes categorizing the dynamics of the communications channel into one of at least two groups based on the estimate.
    Type: Application
    Filed: February 19, 2004
    Publication date: April 24, 2008
    Inventors: Steven L. VanLaningham, Jeffrey A. Barton, James A. Stevens, C. David Young
  • Patent number: 7362801
    Abstract: Noise and signal-to-noise ratio (SNR) estimation are relatively straightforward tasks. However, when SNR is small, systematic errors in measurement may result in over-estimation of SNR, which also occurs during runtime monitoring of SNR. Here, sufficient numbers of bits have been preassigned to each channel using QAM modulation scheme. Therefore, SNR relative to QAM lattice size depends on the noise margin and the desired (bit error rate) BER. If a relatively small margin is desired, similar measurement errors may result in over-estimation of SNR. Another problem that arises is that the variance of the noise estimator is relatively high. Therefore, SNR estimates may vary by several dB, and there is only 50% confidence in the usual estimators that the actual SNR value will not be worse than that estimated. Thus, a computationally efficient method for SNR estimation that also allows for specification of a confidence level in the estimates is provided.
    Type: Grant
    Filed: December 18, 2003
    Date of Patent: April 22, 2008
    Assignee: LSI Logic Corporation
    Inventor: Nagendra K. Goel
  • Patent number: 7362828
    Abstract: A method of optimizing a communication system for receiving and processing an input communication signal includes selecting a first noise margin m to be applied against an external noise present on the input communication signal. The method further includes selecting a second noise margin mi to be applied against an internal noise introduced on the communications signal by the communication system. The second noise margin is a predetermined function of the first noise margin. The method also includes calculating a virtual noise to signal ratio that is a combination of an external noise to signal ratio NSRe, an internal noise to signal ratio NSRi, the first noise margin and the second noise margin. The method further includes adjusting one or more system parameters so as to maintain the virtual noise to signal ratio at a predetermined margin above a required noise to signal ratio.
    Type: Grant
    Filed: November 3, 2003
    Date of Patent: April 22, 2008
    Assignee: Broadcom Corporation
    Inventors: Miguel Peeters, Raphael Cassiers
  • Publication number: 20080089402
    Abstract: The present invention relates to a system for calculating a digital quality index (DQI), which provides a rating on a predetermined scale, indicative of the impairments in a received quadrature amplitude modulated (QAM) signal in a CATV cable system. The DQI system utilizes bit error rates prior to and after forward error correction to calculate the DQI value. To increase the calculation rate, the bit error rates can be estimated using voltage errors, signal to noise ratios and/or average corner error metrics.
    Type: Application
    Filed: September 18, 2007
    Publication date: April 17, 2008
    Applicant: ACTERNA LLC
    Inventors: Gregory W. Massey, Reena Ramname, Kevin J. Oliver
  • Publication number: 20080075157
    Abstract: A method halts transmission and/or reception of a desired signal on a channel in a communication network and samples an analog metric versus time on the channel at a predetermined sample rate. Successively sampled sets of data are stored first to a one dimensional array, each of which set is then stored to a two-dimensional array. The two dimensional array is analyzed in the time domain to determine the presence of impulse noise. Analog parameters represented by values contained in the samples can be analyzed to determine where, with respect to time, impulse noise occurs, and what is the amplitude of the impulse noise as well as AWGN.
    Type: Application
    Filed: September 25, 2007
    Publication date: March 27, 2008
    Inventors: Jim Allen, Tom Cloonan
  • Patent number: 7342958
    Abstract: A system for, and method of, determining channel throughput achievable under superposition coding given a finite, predetermined set of allowed transmission rates and a related system for, and method of, maximizing channel throughput. In one embodiment, the system includes: (1) a noise level calculator configured to calculate associated optimal noise levels for at least some rate subsets of the set of allowed transmission rates and (2) a code feasibility calculator associated with the noise level calculator and configured to determine whether feasible superposition codes exist for the at least some rate subsets given the associated optimal noise levels and thereby identify ones of the at least some rate subsets that are suitable for subsequent wireless transmissions.
    Type: Grant
    Filed: June 24, 2004
    Date of Patent: March 11, 2008
    Assignee: Lucent Technologies Inc
    Inventors: Suman Das, Thierry E. Klein, Sayandev Mukherjee
  • Patent number: 7339986
    Abstract: A method is presented that monitors the quality of a communications channel. The method includes receiving a data signal and establishing a zero reference phase of the received data signal. The method further includes generating a phase-shifted data signal by phase shifting the received data signal relative to the zero reference phase, and sampling the phase-shifted data signal for one or more phase-shift positions. A zero reference phase is reestablished between sampling at each of the phase-shift positions. The method also includes detecting bit errors in the phase-shifted data signal at each of the phase-shift positions in order to provide a communications channel quality measurement. In an embodiment, the method includes generating an eye diagram according to a count of detected bit errors relative to a count of detected bits. The eye diagram characterizes the quality of the communications channel.
    Type: Grant
    Filed: January 30, 2004
    Date of Patent: March 4, 2008
    Assignee: Broadcom Corporation
    Inventors: Jay Proano, Howard Baumer, Chung-Jue Chen, Ali Ghiasi, Vasudevan Parthasarathy, Rajesh Satapathy, Linda Ying
  • Publication number: 20080049821
    Abstract: A modulation scheme deciding apparatus, a receiving apparatus, a modulation scheme deciding method and modulation scheme deciding program can improve a performance of the frame modulation scheme decision without the influence of an error in the modulation scheme decision in each burst and improve throughput of the receiving apparatus. Receiver 100 has modulation scheme deciding apparatus 106, the modulation scheme deciding apparatus 106 including: received quality measuring apparatus 101 that measures received qualities of received data transmitted from a plurality of bursts separated from one frame; frame modulation scheme deciding apparatus 102 that decides a modulation scheme of frame based on received qualities of a plurality of modulation schemes measured in each burst; and burst modulation scheme deciding apparatus 103 that decides the modulation scheme of each burst based on the received quality of received data.
    Type: Application
    Filed: August 28, 2007
    Publication date: February 28, 2008
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventor: Yukiteru MURAO
  • Publication number: 20080049820
    Abstract: A wireless communication method and system using virtual MIMO (“V-MIMO”) are provided. Post processing signal to interference and noise ratios (“SINR”) for a plurality of signals corresponding to a plurality of mobile terminals arranged as a V-MIMO group are estimated. The one of the plurality of mobile terminals having the highest post processing SINR is selected. Wireless communication for the selected mobile terminal is scheduled. The signal corresponding to the selected mobile terminal is cancelled. Post processing signal to interference and noise ratios (“SINR”) for the signals corresponding to the remaining mobile terminals is re-estimated. The one of the remaining mobile terminals having the highest post processing SINR is selected. Wireless communication for the selected remaining mobile terminal is scheduled.
    Type: Application
    Filed: August 22, 2007
    Publication date: February 28, 2008
    Applicant: NORTEL NETWORKS LIMITED
    Inventors: Ming JIA, Jianglei MA, Jianming WU, Peiying ZHU, Wen TONG
  • Patent number: 7336703
    Abstract: A device and method for measuring power of a received broadband signal including narrowband interference in a mobile communication system is provided. An interference eliminator removes the narrowband interference from the received broadband signal through a filter. A power compensator calculates a compensation value for compensating for at least one portion of the received signal removed when the narrowband interference was removed. A received power measurement unit measures power of the received signal received from the interference eliminator, and compensates for a measurement error in the measured power due to the removed at least one portion using the compensation value, and then outputs the received broadband signal having the compensated power.
    Type: Grant
    Filed: June 30, 2004
    Date of Patent: February 26, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jeong-Tae Oh, Jae-Hyok Lee
  • Patent number: 7333535
    Abstract: By allowing the block rate to vary, the existing Asymmetric Digital Subscriber Line (ADSL) system is modified to better address extended reach and higher data rates. A method is disclosed for providing improved reach from the ADSL standard by reducing the block rate from the ADSL standard and providing improved data rate for short loops by increasing the block rate from the ADSL standard.
    Type: Grant
    Filed: November 13, 2002
    Date of Patent: February 19, 2008
    Assignee: Texas Instruments Incorporated
    Inventor: Arthur John Redfern
  • Patent number: 7333537
    Abstract: A system is presented that monitors the quality of a communications channel with mirror receivers. A first receiver and a second receiver, coupled in parallel with the first receiver, receive a data signal transmitted over the communications channel. The second receiver generates an output signal. A signal integrity (SI) processor manipulates the output signal in order to determine the quality of the communications channel. The SI processor samples a phase-shifted version of the output signal, which has a phase shifted relative to a zero reference phase, and analyzes the phase-shifted version of the output signal for bit errors. In an embodiment, the SI processor manipulates the output signal to extract an eye diagram indicative of the quality of the communications channel. The SI processor non-intrusively determines the quality of the communications channel using the second receiver.
    Type: Grant
    Filed: January 30, 2004
    Date of Patent: February 19, 2008
    Assignee: Broadcom Corporation
    Inventors: Jay Proano, Howard Baumer, Chung-Jue Chen, Ali Ghiasi, Vasudevan Parthasarathy, Rajesh Satapathy, Linda Ying
  • Publication number: 20080037620
    Abstract: A method and apparatus for estimating noise for orthogonal frequency division multiplexing (OFDM) are disclosed. A time domain difference signal and a frequency domain difference signal between two consecutive received pilot symbols are calculated. A time domain noise power is calculated from the time domain difference signal and a frequency domain noise power is calculated from the frequency domain difference signal. The time domain noise power and the frequency domain noise power are combined to estimate the noise power.
    Type: Application
    Filed: August 7, 2007
    Publication date: February 14, 2008
    Applicant: INTERDIGITAL TECHNOLOGY CORPORATION
    Inventors: Afshin Haghighat, Seyed M. Hosseinian
  • Patent number: 7330504
    Abstract: A system and method for adjusting the power control target for a spread-spectrum communication system 110 is disclosed. A preferred embodiment comprises correcting a power control target 128 based upon the difference between a filtered series of actual error signals 124 and the expected number of errors 126 over a properly determined time window. By using a filtered series of actual error signals, the power control target update step-size is adaptive to the channel conditions, and the power-rise is reduced, thereby reducing power requirements and signal dropouts. The invention finds application, for example, in personal communication devices such as cellular telephones and may be implemented using a digital signal processor (DSP).
    Type: Grant
    Filed: November 25, 2002
    Date of Patent: February 12, 2008
    Assignee: Texas Instruments Incorporated
    Inventors: Wei Lin, Yuan Kang Lee
  • Patent number: 7324783
    Abstract: A method, arrangement (512) and communication receiver (500) for SNIR estimation of a received signal, by: deriving (512A) an estimation {circumflex over (Z)} of SNIR of the received signal in accordance with the relation Z ^ = [ E ? { ? r ? ( t ) ? } ] 2 E ? { r 2 ? ( t ) } - [ E ? { ? r ? ( t ) ? } ] 2 , where E represents mean value and r(t) represents the level of the received signal; and correcting (512B, 512C) the estimation {circumflex over (Z)} to produce a corrected estimation Z based on the relation Z=?({circumflex over (Z)})×{circumflex over (Z)}, where ?({circumflex over (Z)}) represents a correction factor. The estimation may be corrected by calculating the correction factor, retrieving the correction factor from a predetermined table (512B) or retrieving the corrected estimation from a predetermined table. The correction may be effected by adding to a logarithmic estimation a logarithmic correction factor.
    Type: Grant
    Filed: November 25, 2002
    Date of Patent: January 29, 2008
    Assignee: IPWireless, Inc.
    Inventor: Nicholas Anderson
  • Patent number: 7321616
    Abstract: A method and apparatus for reducing processing requirements of a pool of soft modems is disclosed. In one embodiment, the method comprises queuing one or more retrain requests and responding to the queued retrain requests within a period of time to one or more modems that correspond to the queued retrain requests.
    Type: Grant
    Filed: December 23, 2003
    Date of Patent: January 22, 2008
    Assignee: Intel Corporation
    Inventor: Robert David Wachel
  • Publication number: 20080002793
    Abstract: A system and method are provided for auto-squelching digital communications. The method receives digital information from a source node. If the receive channel is corrupted, an alarm condition is detected that is associated with the received digital information. The method transmits an alarm-condition signal to a destination node, and in response to transmitting the alarm-condition signal, maintains a valid link to the destination node. For example, detecting the alarm condition may include: comparing a frequency associated with the recovered clock signal, with a reference frequency; and, detecting a variance between the recovered clock signal frequency and the reference frequency. Alternately, loss of signal, loss of lock, out of band, and run length alarm conditions may be detected. The alarm-condition signal that is transmitted may be a serial data stream of information such as all “0”s data, all “1”s data, or alternating “0”s and “1”s data for example.
    Type: Application
    Filed: June 29, 2006
    Publication date: January 3, 2008
    Inventors: Timothy Eric Giorgetta, Madjid A. Hamidi
  • Patent number: 7315574
    Abstract: A multi-speed jittered signal generator (216, 400) that generates a full-speed jittered signal (404) by scaling a low-speed jittered signal (420) using a frequency scaler (428). The low-speed jittered signal is created by injecting a modulation signal (416) into a reference signal (412) using a jitter injector (432). Injecting jitter into a low-speed reference signal allows the full-speed jittered signal to be of higher quality than conventional jitter signals created by injecting jitter information into a full-speed reference signal. The multi-speed jittered signal generator may be used as part of a testing system (208) for testing various circuitry, such as high-speed serializer/deserializer circuitry (220).
    Type: Grant
    Filed: April 26, 2005
    Date of Patent: January 1, 2008
    Assignee: DFT Microsystems, Inc.
    Inventors: Mohamed M. Hafed, Geoffrey D. Duerden, Gordon W. Roberts
  • Patent number: 7313167
    Abstract: An improved approach to noise estimation permits, for example, tighter closed-loop power control in a wireless communication network with attendant improvements in transmit power efficiency and network capacity. In an exemplary embodiment, the received signal-to-noise ratio (SNR) of a data signal is estimated based on noise samples obtained from one or more other signals received in association with the data signal. In general, these associated signals are characterized by the receiver's ability to extract like valued samples from them, such that pairs of these like valued signal samples may be subtracted, thereby canceling their deterministic signal components and leaving only difference values representative of the non-deterministic noise components of the signal samples.
    Type: Grant
    Filed: September 30, 2002
    Date of Patent: December 25, 2007
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Young C. Yoon, Shiau-He Shawn Tsai
  • Patent number: 7313392
    Abstract: The present invention provides a mobile station apparatus. The mobile station apparatus comprises an RF transmitting/receiving module, a display module, a memory comprising an RSSI database, and a control program. When the mobile station apparatus moves along a path comprising plural candidates of communication locations, the control program records a plurality of RSSIs, which are received by the RF transmitting/receiving module from the candidates along the communication locations, and at least one path parameter in the RSSI database, and then according to a predetermined display algorithm, the control program controls the display module to display at least one recorded RSSI and the corresponding path parameter as a reference, based on which the mobile station apparatus selects a communication location candidate for providing the mobile communication service.
    Type: Grant
    Filed: July 16, 2004
    Date of Patent: December 25, 2007
    Assignee: BENQ Corporation
    Inventor: Steven D. Cheng
  • Publication number: 20070291831
    Abstract: A method and apparatus for correcting a Signal-to-Noise Ratio (SNR) of an antenna of a mobile terminal, which can detect if a Micro-Electro Mechanical System (MEMS) reconfigurable antenna for wireless communication contacts a foreign substance, to correct an SNR of the antenna. The mobile terminal having the MEMS reconfigurable antenna changes the MEMS reconfigurable antenna and calculates an SNR during execution of the wireless communication, thereby setting the MEMS reconfigurable antenna to an antenna form corresponding to a greatest SNR.
    Type: Application
    Filed: June 19, 2007
    Publication date: December 20, 2007
    Applicant: Samsung Electronics Co., Ltd.
    Inventors: Chang-Seok LEE, Boris Kisselev, Kang-Hoon Lee, Dae-Hyun Sim, Dong-Jun Lee
  • Patent number: 7310369
    Abstract: A method for estimating an SNR-related parameter, such as ES/N0, from one or more symbols. The number of symbols within a predetermined number of symbols that fall within one or more collection areas is counted. The count is then associated with a value of the SNR-related parameter. This association may be performed through one or more lookup tables. In one application, a scaling factor is derived from the count. The scaling factor may be used to scale symbols before they are quantized and inputted into a trellis decoder such as a log-MAP decoder.
    Type: Grant
    Filed: May 30, 2001
    Date of Patent: December 18, 2007
    Assignee: Conexant Systems, Inc.
    Inventors: Abraham Krieger, Ramaswamy Murali, Donald Brian Eidson, Sachar Kons
  • Publication number: 20070274378
    Abstract: A method to determine bit error rate (BER) for a given channel of a communication system includes determining a first statistical representation of at least one deterministic source of noise for the given channel. A parametric statistical representation having parameters that model non-deterministic noise is defined for the given channel and values for the parameters of the parametric statistical representation are estimated to provide a second statistical representation for the non-deterministic noise based on at least one of measurements and simulations performed for the given channel. The BER of the given channel is estimated as a function of the first and second statistical representations.
    Type: Application
    Filed: May 26, 2006
    Publication date: November 29, 2007
    Inventor: Nirmal C. Warke
  • Patent number: 7302024
    Abstract: In a digital receiver for receiving COFDM modulated television signals or the like, consecutive samples are compared with a detection threshold and the number of samples having amplitudes greater than the threshold is determined. This is compared with a further threshold and, if the number of such samples exceeds the further threshold, affected samples are blanked to zero. Similarly, an automatic gain control loop is disabled when the samples are blanked. A demodulator forms the difference in phase of pilot carriers from symbol to symbol. If the variance of the phase differences exceeds an averaged value, this indicates the presence of impulsive noise and is used to inhibit signal correction techniques within the demodulator. Noise energy is thus reduced and propagation of effects resulting from impulsive noise from symbol to symbol is substantially reduced.
    Type: Grant
    Filed: October 30, 2002
    Date of Patent: November 27, 2007
    Assignee: Intel Corporation
    Inventor: Bernard Arambepola
  • Publication number: 20070263712
    Abstract: The claimed subject matter relates to estimating noise variance associated with a transmitter. For example, the noise variance can be estimated in connection with determining performance parameters associated with a transmitter. Determining noise variance can include the acts of estimating phase alteration of a received signal through utilization of a least squares-based phase estimation algorithm. Determining noise variance can also include the act of determining an unbiased estimation of noise variance as a function of the estimated phase alteration.
    Type: Application
    Filed: June 14, 2006
    Publication date: November 15, 2007
    Inventors: Fuyun Ling, Thomas Sun, Raghuraman Krisnamoorthi, Durk L. van Veen, Murali Ramaswamy Chari
  • Publication number: 20070248155
    Abstract: Embodiments are directed to a wireless receiver system that utilizes a special structure of pilot symbols used for synchronization and channel estimation in transmission packets to measure noise power at the receiver. The periodicity of the pilot signal sequences is used to extract the noise power from the received signal. Such extraction is achieved by subtracting the received signals from two pilot slots which are separated by the known periodicity of the training sequence. This method relies on the fact that desired signal and system interference signals will cancel out after the subtraction process. Measuring the power of the residual signal after subtraction represents the estimate of the noise power. Several consecutive such residual signals can be first summed up before measuring the power to improve the estimate of the noise power at the receiver.
    Type: Application
    Filed: April 19, 2007
    Publication date: October 25, 2007
    Inventors: Djordje Tujkovic, Ying Xia, Robert Lorenz, Sriram Mudulodu
  • Patent number: 7277477
    Abstract: A method and system that communicates adaptive transmit-side filter updates between a receiver and transmitter inserts additional versions of control codes into a back channel for encoding updates. Since the control codes are required in the back channel, no additional bandwidth of the back channel is used to communicate the updates.
    Type: Grant
    Filed: June 21, 2002
    Date of Patent: October 2, 2007
    Assignee: Cisco Technology, Inc.
    Inventor: Bilal Ahmad
  • Patent number: 7277498
    Abstract: In the code word mapping operation of a radio communication system, mapping patterns are provided for different S/N ratios, the code word bits produced from a coder are not equally assigned to multi-level modulation bits, but weighted according to the resistance of multi-level modulation bits to error before being assigned, and the mapping patterns are switched in accordance with S/N. Since the code word mapping method is updated so that the error rate can be always minimized according to the situations of a propagation path and S/N ratio, communication can be made with high communication quality.
    Type: Grant
    Filed: July 29, 2002
    Date of Patent: October 2, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Seishi Hanaoka, Takashi Yano
  • Patent number: 7274735
    Abstract: A method is provided to provide data to automatically estimate channel performance in a communication system if a different order constellation is used comprising the steps of: receiving an input signal from the channel; passing the input signal to a slicer having an output signal; determining signal noise by taking the difference between the input signal and output signal; identifying a beginning of a noise event when the signal noise is greater than a predefined first threshold; identifying an end of a noise event when the signal noise is less than a predefined second threshold; and providing for output the beginning of the noise event and the end of the noise event. Other systems and methods are disclosed.
    Type: Grant
    Filed: October 18, 2002
    Date of Patent: September 25, 2007
    Assignee: Texas Instruments Incorporated
    Inventors: Itay Lusky, Daniel Wajcer, Yosef Bendel, Yigal Bitran, Naftali Sommer, Ofir Shalvi, Zvi Reznic, Ariel Yagil, Eli Haim
  • Patent number: 7257173
    Abstract: A description of signal behavior in the vicinity of a time and voltage of interest is produced by defining a region in the (time, voltage) plane that is a closed straight sided figure whose vertices are identified by threshold crossings offset for the voltage of interest and clocked by time delays offset from a clock time of interest. A first set of latches clocked by the time delays accumulates the state of signal behavior relative to the threshold voltages as it occurs, and their contents are subsequently transferred to a second set of latches at the start of a new clock cycle, allowing a new accumulation to begin and also allowing a detection logic circuit to operate on a unified and completed collection of indicators of what the just concluded description amounts to. The detection logic circuit responds to the combinations of latched indications to produce a signal corresponding to that description.
    Type: Grant
    Filed: April 28, 2004
    Date of Patent: August 14, 2007
    Assignee: Agilent Technologies, Inc.
    Inventors: Glenn Wood, David D. Eskeldson
  • Patent number: 7254496
    Abstract: A signal-to-interference ratio (SIR) estimator for estimating a SIR of baseband signals which are received and processed by a data demodulator to provide demodulated signals to the SIR estimator. The SIR estimator receives the demodulated symbols from the data demodulator and estimates the average signal power of the demodulated symbols as a function of a median based average power value md and a mean based average power value me of the demodulated symbols for each quadrant of a quadrature phase shift keying (QPSK) constellation. The function is used to determine a minimum value m between md and me. The SIR estimator estimates the average effective interference power of the demodulated symbols and calculates the SIR by dividing the estimated average signal power of the demodulated symbols by the estimated average effective interference power of the demodulated symbols.
    Type: Grant
    Filed: May 9, 2006
    Date of Patent: August 7, 2007
    Assignee: InterDigital Technology Corporation
    Inventors: Sung-Hyuk Shin, Ariela Zeira
  • Patent number: 7254170
    Abstract: Noise measurements are made within a fraction of a single symbol period of a longest orthogonal code symbol. A control processor identifies an unoccupied code having a spreading factor that is less than a longest spreading factor for the system. A despreader measures symbol energy based on the unoccupied code and a noise estimator generates noise estimations based on the measured symbol energies. The subscriber station uses similar techniques in order to perform channel estimations within a period that is a fraction of a symbol period of a longest-spreading-factor code.
    Type: Grant
    Filed: November 7, 2002
    Date of Patent: August 7, 2007
    Assignee: Qualcomm Incorporated
    Inventors: Da-shan Shiu, Durga P. Malladi, Srikrishna Bhashyam
  • Patent number: 7254169
    Abstract: A loss-of-signal (LOS) condition is detected by sampling input data for a predetermined time period, comparing a magnitude of the sampled input data to a threshold signal strength level, and asserting a LOS indication if the number of samples that have signal strength less than the threshold signal strength level is less than a predetermined value.
    Type: Grant
    Filed: December 11, 2001
    Date of Patent: August 7, 2007
    Assignee: Silicon Laboratories Inc.
    Inventors: Philip David Steiner, Michael H. Perrott, Vadim Gutnik
  • Patent number: 7254165
    Abstract: Methods and systems provide for operating a modem receiver such as an ADSL modem receiver. As incoming data signals are received, a decoding scheme is selected from a plurality of decoding schemes based on a predetermined downstream data rate. In one approach a soft receiver architecture of an ADSL modem is able to select between relatively complex decoding schemes and relatively simple decoding schemes based on signal-to-noise ratio (SNR).
    Type: Grant
    Filed: August 7, 2003
    Date of Patent: August 7, 2007
    Assignee: Intel Corporation
    Inventors: Qian Xie, Huaiyu Zeng
  • Patent number: 7254217
    Abstract: A fault associated with a communication medium is analyzed by correlating a first set of information indicative of echo associated with the communication medium with a second set of information indicative of echo. The fault is characterized based on the correlation between the first set of information and the second set of information. The first set of information and the second set of information can include echo canceller coefficients generated by an echo canceller coupled to the communication medium.
    Type: Grant
    Filed: June 16, 2003
    Date of Patent: August 7, 2007
    Assignee: ADC DSL Systems, Inc.
    Inventors: Michael J. Rude, Ronald R. Gerlach, Mo-Ching Justine Lau, Tiet Pham, William W. Lu
  • Patent number: 7251572
    Abstract: Discovery of RJ assumes an Adjusted TIE Record for TJ from which DDJ has been removed. What remains is PJ+RJ, from whose Fourier Transform PJ is ‘synthetically de-convolved’ to leave just RJ: Calculate the Power Density Spectrum of PJ+RJ, and determine a threshold that indicates a PJ component. Identify in the PDS the largest frequency component that exceeds the threshold, otherwise there is no significant PJ and PJ+RJ can be taken as RJ. If a frequency component exceeds the threshold, take the largest and calculate what the convolution of it with the FT of the Transition Pattern would be if this circumstance were to occur in isolation, and then remove it from PJ+RJ. Repeat with continued iterations, until there are no further PJ components.
    Type: Grant
    Filed: July 14, 2006
    Date of Patent: July 31, 2007
    Assignee: Agilent Technologies, Inc.
    Inventors: Steven D Draving, Allen Montijo
  • Patent number: 7248655
    Abstract: A receiving unit (2) receives a modulated signal resulting from modulating a carrier signal with a digital encoded train resulting from error-correction encoding a digital signal train. A demodulating unit (4) demodulates the digital encoded train from the received modulated signal. A decoding unit (8) decodes the digital signal train from the demodulated digital encoded train. The receiving unit (2) outputs a received-signal strength indicative signal indicative of the received-signal strength of the modulated signal. During demodulating, a bit error rate computing unit (18) of the decoding unit (8) computes a bit error rate. The received-signal strength indicative signal and the bit error rate are inputted to a control unit (14), and, on the basis of these inputs, it is judged which one of the receiving conditions defined by received-signal strength indicative signals and bit error rates, the current receiving condition corresponds to.
    Type: Grant
    Filed: April 24, 2003
    Date of Patent: July 24, 2007
    Assignee: TOA Corporation
    Inventor: Tomohisa Tanaka
  • Patent number: 7248627
    Abstract: A link quality estimating method and apparatus adopts a fading value to modify an estimated link quality of a channel thereby obtaining a measure being very close to the real link quality. The method is implemented by utilizing two sequentially received long training symbols to derive two sets of subcarrier gain values Hk,1 and Hk,2. Based on the subcarrier gain values Hk,1 and Hk,2, parameters representing the estimated channel gain value (A), the fading value (F) and the noise quantity (B) of the channel are all calculable. With these parameters, the link quality (LQ) of said communication channel is derived.
    Type: Grant
    Filed: August 4, 2003
    Date of Patent: July 24, 2007
    Assignee: Mediatek Incorporation
    Inventor: Mao-Ching Chiu
  • Patent number: 7245878
    Abstract: A method of detecting a silent frame at a mobile station in a GSM transmission is disclosed. The method comprises first receiving a data burst intended for the mobile station. Then, a signal-to-interference-and-noise ratio (SINR) is determined for the data burst. If the SINR is below a predetermined threshold, then the data burst is determined as from a silent frame.
    Type: Grant
    Filed: October 28, 2003
    Date of Patent: July 17, 2007
    Assignee: Spreadtrum Communications Corporation
    Inventors: Jingdong Lin, Yan Zhang, Jiayi Zhuang, Jian Cheng
  • Patent number: 7242761
    Abstract: A system for determining the transmit power of a communication device operating on a twisted pair subscriber line includes a communication server coupled to a first subscriber line and a second subscriber line. The communication server comprises a communication device that communicates a signal using the first subscriber line. A memory coupled to the communication server stores noise information and cross-channel-coupling information for the first subscriber line and the second subscriber line. A processor coupled to the memory determines the transmit power of the communication device based upon the noise information and the cross-channel-coupling information.
    Type: Grant
    Filed: July 24, 2003
    Date of Patent: July 10, 2007
    Assignee: Cisco Technology, Inc.
    Inventor: Celite Milbrandt
  • Patent number: 7230981
    Abstract: An integrated data jitter generator for the testing of high speed serial interfaces is provided. A transmit timing generator for use in a transmit data path includes a high frequency clock generator such as a phase-locked loop or a delay-locked loop having an input for receiving an oscillator or reference clock input. A clock modulator receives both an existing low frequency modulation signal and a high frequency modulation signal. A high-speed modulated clock signal is generated to enable jitter testing by a downstream-coupled receiver. Fixed frequencies such as 3, 6, 125, 150, 250, 300, 750, or 1500 MHz are used for the high-speed modulation signal, but any high-speed modulation frequency can be used to generate the desired amount of jitter. Likewise, the amplitude of the high frequency modulation signal can also be varied as desired.
    Type: Grant
    Filed: May 9, 2003
    Date of Patent: June 12, 2007
    Assignee: STMicroelectronics, Inc.
    Inventor: John P. Hill
  • Patent number: 7221704
    Abstract: A digital circuit configured to spread a clock train spectrum includes a clock configured to generate the clock train, and a variable divider configured to divide the frequency of the clock train by a temporally-varying-divider value to modulate the clock train and generate a dithered clock train. The circuit further includes a first accumulator configured to accumulate the dithered clock train to generate a frequency modulation waveform, and a second accumulator configured accumulate the frequency modulated waveform to generate a phase modulation signal. The circuit further includes a phase-value calculator configured to calculate the temporally-varying divider value based on the phase modulation signal; and a closed-loop control circuit configured to track and filter the modulation of the dithered clock train to generate a second clock train that is the spread spectrum of the first mentioned clock train.
    Type: Grant
    Filed: October 6, 2005
    Date of Patent: May 22, 2007
    Assignee: Marvell World Trade Ltd.
    Inventor: Jody Greenberg
  • Patent number: 7218695
    Abstract: The invention relates to a method and device for estimating an estimated value (U2max) dependent on the maximum (Umax) of a single-frequency signal sampled via a succession of sampled values (d(n)), wherein each of a predetermined number (N) of sampled values (d(n)) is squared and the predetermined number (N) of squared sampled values (d2(n)) is summated.
    Type: Grant
    Filed: October 21, 2002
    Date of Patent: May 15, 2007
    Assignee: Rohde & Schwarz GmbH & Co. KG
    Inventor: Thomas Kuhwald
  • Patent number: 7215703
    Abstract: Digital calculation of an RSSI value begins by digitally calculating a magnitude of a signal (e.g., a received RF signal or representation thereof). The process then continues by filtering the magnitude of the signal to produce a filtered magnitude signal. The process then continues by determining a coarse RSSI value of the filtered magnitude signal, wherein the coarse RSSI value indicates a sliding window of RSSI values. Once the coarse RSSI value is obtained, the process continues by determining a fine RSSI value within the sliding window of RSSI values. The process concludes by summing the fine RSSI value with the coarse RSSI value to produce a digital RSSI value.
    Type: Grant
    Filed: February 14, 2003
    Date of Patent: May 8, 2007
    Assignee: Broadcom Corporation
    Inventors: Henrik T. Jensen, Brima B. Ibrahim
  • Patent number: 7203459
    Abstract: Methods, apparatus, and systems for mode assignment and mode adaptation to channel conditions are provided which are based on estimations of real signal-to-noise ratios (SNR) for each frequency carrier bearing information during a data transmission session. The invention utilizes two principal procedures: signal-to-noise ratio (SNR) estimation, and a corresponding mode assignment. SNR estimation is obtained by an averaging of squared Euclidean distances between normalized received signals and reference signals corresponding to either current hard decisions from the output of a demodulator or soft decisions provided by a decoder, for each frequency carrier bearing random information. Using the SNR estimations, various algorithms for determining mode assignment are provided.
    Type: Grant
    Filed: April 3, 2003
    Date of Patent: April 10, 2007
    Assignee: PCTEL, Inc.
    Inventors: Yuri Goldstein, Yuri Okunev
  • Patent number: 7190741
    Abstract: Method and apparatus for estimating signal-to-noise ratio (SNR) ? of a composite input signal e(t) on a phase-modulated (e.g., BPSK) communications link. A first demodulator receives the composite input signal and a stable carrier signal and outputs an in-phase output signal; a second demodulator receives the composite input signal and a phase-shifted version of the carrier signal and outputs a quadrature-phase output signal; and phase error ?E(t) contained within the composite input signal e(t) is calculated from the outputs of the first and second demodulators. A time series of statistically independent phase error measurements ?E(t1), ?E(t2), . . . , ?E(tk) is obtained from the composite input signal subtending a time interval ?t=tk?t1 whose value is small enough such that ?(t) and ?(t) can be taken to be constant in ?t.
    Type: Grant
    Filed: October 21, 2002
    Date of Patent: March 13, 2007
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Robert M. Manning
  • Patent number: 7187942
    Abstract: A desired SIR control part presets the desired SIR value in a way that it decides to this end the degree of follow-up of the desired SIR by the received SIR (measured value), by reading out a desired communication quality value from a demodulating part, reading out a measured communication quantity value from a communication quality measuring part, reading out a desired SIR value from a memory and reading out a measured SIR value from an SIR measuring part. Thus, it is possible to quickly and smoothly cope with the occurrence of a change in the communication environment in the wireless communication in a W-CDMA system or the like between the base station and the mobile station.
    Type: Grant
    Filed: December 15, 2003
    Date of Patent: March 6, 2007
    Assignee: NEC Corporation
    Inventor: Taisuke Hosokawa
  • Patent number: 7184500
    Abstract: Combining signals includes receiving a plurality of groups of signals at a plurality of antennas at a mobile device, where each group of signals includes a plurality of signals, and each signal includes a time slot. The following is repeated for each group of signals of the plurality of groups of signals. An adjustment associated with a time slot of each signal is set. Each signal of the group of signals is adjusted at the time slot in accordance with the adjustment associated with the time slot. A signal quality associated with each time slot of each signal of the group of signals is established, and an optimal adjustment in accordance with the signal qualities is determined. The signals are adjusted in accordance with the optimal adjustment.
    Type: Grant
    Filed: December 30, 2002
    Date of Patent: February 27, 2007
    Assignee: Magnolia Broadband Inc.
    Inventors: Yingxue Li, Haim Harel
  • Patent number: 7177600
    Abstract: Disclosed are an apparatus and method for testing performance of a mobile station having a global positioning system (GPS) mounted therein. The method provides for virtually changing parameters requited for a registration at a base station so that the mobile station excludes the registration and directly enters a test state with an idle mode, and testing the performance of the mobile station in the idle mode test state. Accordingly, no re-boot is necessary to register with the base station upon completion of the test.
    Type: Grant
    Filed: June 24, 2003
    Date of Patent: February 13, 2007
    Assignee: LG Electronics Inc.
    Inventors: Do-Woo Kang, Hun-Taek Han, Hyong-won Kim, Tae-Sook Yoon